Steerer Tube Diameter / Stem Steerer Diameter?

So I am looking into getting a Straitline SSC Stem for a Norco Ryde with RST Dirt forks. The stem says it has a 1.5" steerer diameter, but the forks say their steerer is 28.6mm or 1.125984". I am not an expert with these kind of dimensions but does this mean the stem is too big for the steerer tube? Thanks for your help.

you don't need to be an expert(or anywhere remotely close) to see that 1.5 is larger than 1.125. as a matter of fact, i'd be willing to bet that if your parents were brother and sister, you could still tell...